1. Field of the Invention
The present invention pertains to mesh network communication systems and methods and, more particularly, to determining the location of a remote subscriber unit in a mesh network to permit communication between remote subscriber units in an efficient manner.
2. Brief Discussion of the Related Art
In currently employed mesh network communication systems containing remote subscriber units, each mesh remote subscriber unit is given, a priori, an address. A remote subscriber unit can enter a mesh network at any node, and use the network to communicate with any fixed user.
One problem faced in such systems is that a first remote subscriber unit, when entering a mesh network, typically would want to communicate with a second remote subscriber unit whose present location is unknown to the first remote subscriber. That is, the second remote subscriber unit may not be in the same mesh network as the first remote subscriber unit; and, even if the second remote subscriber unit is in the same mesh network, the second remote subscriber unit may not be reachable at its address. In addition, such systems as currently proposed are typically carrier sense multiple access (CSMA) systems which do not permit simultaneous access to a node. Accordingly, if one remote subscriber unit is accessing a node with a voice, or with a streaming video signal, other remote subscriber units must wait until there is a “free time interval,” that is, a time period in which no remote subscriber unit is using the channel to the node, in order to access the node.
The prior art systems, as described above, do not determine the location of a remote subscriber unit in a simple and efficient manner to permit efficient and direct communication between remote subscriber units.
U.S. Pat. No. 7,016,328 to Chary et al, U.S. Pat. No. 7,050,819 to Schwengler et al and U.S. Pat. No. 7,085,241 to O'Neal et al, are representative of prior art communication systems having the disadvantages described above. The Chary et al patent discloses a mobile user accessing a mesh network where the mobile user can move from node to node during a conversation by the use of a handover procedure. When the mobile user first accesses the mesh network, the mobile user provides the entrance node with its client (ID) information. A backbone network is employed to contact the destination node at which time a communications path is set up. The Chary et al patent does not disclose how one mobile user entering a mesh network can find a second mobile user in the mesh network where each of the mobile users is at a random location, and describes a centralized flow control as opposed to node to node flow control. The Schwengler et al patent discloses a mobile user accessing a mesh network where the mobile user is detected by the mesh network and, with the use of GPS and triangularization, the physical location of the mobile user is determined. Based on the determined location of the mobile user, a transmit frequency is selected. There is no disclosure in the Schwengler et al patent as to how one mobile user can access another mobile user located in the mesh network or in another mesh network. The O'Neal et al patent describes routing techniques used to communicate with a mobile user assuming that initially a user communicating with the mobile user knows the mobiles user's address. The O'Neal et al patent does not disclose how to initially locate the mobile user or how to initiate a call to the mobile user who can be anywhere.
In a white paper, Copyright 1992-2001, Cisco Systems, Inc. describes mobile communication, referred to as Mobile IP, where a home agent (router) serves as an anchor point for communication with a mobile node, such as a cell phone, PDA or laptop, and tunnels packets from a device on the Internet to the mobile node, via the home agent; a procedure which has the disadvantage of being an inefficient use of bandwidth and time. The home agent is updated with location information periodically over a regular basis, not continually dependent on movement of the mobile node, which has the disadvantage of unnecessarily clogging the network.
In view of the above, it should be appreciated that there is a great need for a system and method for determining the location of a mesh remote subscriber unit operating in a mesh network communication system, including one or more mesh networks, to thereby allow remote subscriber units to communicate with each other when a remote subscriber unit is moving, without clogging the system.